"Microsoft and Perceptive Pixel Inc. (PPI) today announced that they have entered into a definitive agreement under which Microsoft will acquire PPI, a recognized leader in research, development and production of large-scale, multi-touch display solutions." Yes, Jeff Han is now a Microsoft employee. This demo still amazes me - from 2006. Before the iPhone. Before Android. Before the iPad. Remember that the next time you wind up in a discussion about who supposedly invented what.

"I think you've missed my point because wind speed should never need to come into the equation unless you're using the general purpose front mic (which, quite frankly, is a silly idea)."

Firstly, if the mic picks up the frequencies you need, then it's not silly at all. If it doesn't, then you'll need something more specialised, but as a hobby project it makes plenty of sense to start out with off the shelf equipment when possible.

Secondly, any acoustic system will necessarily be affected by windspeed regardless of the equipment you use. I think you may have misunderstood me, I'm not talking about noises caused by wind, I'm talking about the physics of audio propagation and how wind will offset the triangulation of a ping from it's true origin.

Therefore, IF wind is anticipated (ie outdoors), then it must be compensated or it will affect the accuracy of the system.

Edit:

Neolander is talking about detecting taps on against a board, but I'm talking about tracking a stylus in 2d/3d space using emitors and microphones. It could scale to large natural areas like the football example, or maybe even in swimming pools.

Of course, it makes more sense to use radio instead, but the discussion was about DIY projects, where audio is easy to do.

you have completely missed the point because we're talking about this being a possible alternative for embedded systems. Thus everything you've posted is completely irrelevant:

Firstly, if the mic picks up the frequencies you need, then it's not silly at all. If it doesn't, then you'll need something more specialised, but as a hobby project it makes plenty of sense to start out with off the shelf equipment when possible.

Engineering smart phones are not "hobby projects". So nothing you've said here bares any relevance to anything I was discussing earlier.

Secondly, any acoustic system will necessarily be affected by windspeed regardless of the equipment you use. I think you may have misunderstood me, I'm not talking about noises caused by wind, I'm talking about the physics of audio propagation and how wind will offset the triangulation of a ping from it's true origin.

Therefore, IF wind is anticipated (ie outdoors), then it must be compensated or it will affect the accuracy of the system.

I repeat: the mic would be inside the casing. You simply wouldn't want nor need to use the general purpose mic for this. Thus, unless the phone itself has it's own internal weather patterns, then wind speed is not an issue what-so-ever. Period.

Neolander is talking about detecting taps on against a board, but I'm talking about tracking a stylus in 2d/3d space using emitors and microphones.

Exactly, you've missed the point of what we're discussing. What you're chatting about is completely irrelevant to anything which I was discussing earlier.

Fair enough this idea has scope beyond what I'm specifically chatting about (I never disputed that - in fact I've actually stated this already), however don't tell me that my points were wrong when you're quite clearly chatting about a whole other topic than I am.

So please, if you want to disagree with me (and you're more than welcome to ), then please do so with the same context to the points I raised. If you want to discuss a related tangent (as you have done and which is also an interesting topic), then don't raise it as a counter argument. That's all I ask

Thank you for clarifying, however I already know what your talking about. Please quit being so patronising and insisting that I am the one missing the point. I am the OP of the thread, we're covering a variety of approaches for DIY tracking - you're obviously welcome to criticise whatever you like and better yet come up with your own ideas.

Edit: Maybe I'm being too abrasive, but I don't like being spoken down to and it feels like that's what you are doing.